Carborundum Powder

This glittery, abrasive, extremely fine and almost diamond-hard grit is carborundum powder or silicon carbide. Although silicon carbide does occur in nature in the form of the mineral moissanite it is extremely rare, and it is one of only a few minerals that was created synthetically before it was discovered in nature. Because naturally occurring silicon carbide is found in such small amounts it is largely used as a gemstone, and all the silicon carbide used industrially today is synthetic.

Carborundum was the trade name given to artificial silicon carbide powder when it was first synthesised in 1891 by American inventor Edward Acheson. After many years working on inventions such as Thomas Edison’s incandescent light, Acheson reportedly discovered this abrasive material whilst trying to make a synthetic diamond replacement (cubic zirconium) by heating clay and coke in an iron bowl with a carbon arc light. Whilst he did not manage to produce cubic zirconium, his experimental process produced some mysterious ‘bright specks’ that turned out to have an interesting combination of exceptional hardness, infusibility and incombustibility that made them a very useful industrial abrasive. Acheson went on to patent this process and produce grinding wheels, sandpapers, whetstones and knife sharpeners whose hardness and abrasive properties were second only to diamond.

This material was later picked up by artists and artisans of all descriptions and found uses in practices as varied as printmaking, gemmology and ceramics. In lithography and printmaking carborundum was able to abrade the surface of large and durable metal printing plates more deeply and coarsely than sandpaper or glass could, allowing for larger printing surfaces that could hold ink superbly. It is also used by gemmologists and lapidarists for gem and stone cutting and polishing.

More recently, silicon carbide’s wear resistance and non-slip qualities have made it particularly useful in road surfaces, floor treads and car brakes, as well as parts for pumps and rocket engines. Because of its high temperature and corrosion resistance, silicon carbide composites are used in gas turbines and refractory linings and heating elements for industrial furnaces. Silicon carbide has also become a mainstay of the electronics industry where it is used in the production of semiconductors used in light-emitting diodes (LED lights), for example.